The invention is a coupling which may be connected with pressure on the male half. Typically, the invention is used on agricultural implements such as tractors or small versions thereof. The male half of the coupling includes a relief valve which is operated during connection with the female thus enabling easier connection with a pressurized male half.
International Publication WO 98/19097 published May 7, 1998 and filed Oct. 17, 1997 by applicant STUCCHI S.R.L. discloses a male half of the coupling in FIG. 1 thereof which includes a seal 40 carried in a fixed body 32, a piston 37, a safety valve 37 abutting an inner element 34, and, a relief valve 46 being a ball valve 46 actuated by pin 45 for venting to chamber 48. U.S. Pat. No. 6,026,857 issued Feb. 22, 2000 to Stucchi claims priority based on International Publication WO 98/19097. U.S. Pat. No 5,592,970 to Stucchi et al. issued Jan. 14, 1997 discloses structure similar to WO 98/19097 except the relief valve and pin are missing. The ""970 patent is directed to preventing the blowout of seal 40 by covering it with bush 10.
The structure disclosed in WO 98/19097 will leak by the ball valve 46 and the interface between valve 73 and inner body member 34 at low pressures, for example, below 500 psig. Leaking around valve 46 and the interface negates the purpose of the relief valve 46 as the volume available will be filled. Leakage may occur at pressures greater than 500 psig but the increased pressures tend to enhance the metal to metal seals employed by STUCCHI S.R.L. in WO 98/19097.
U.S. Pat. No. 3,498,324 to Breuning discloses secondary valves which first engage each other and open causing a flow through the secondary flow passages from the high pressure side to the low pressure side of the coupling. The valves are in the male and the female halves of the coupling. U.S. Pat. No. 3,570,543 to Ekman discloses a coupling halving pressure relief valves in both the male and female halves.
U.S. Pat. No. 5,159,955 to Ekman, in FIGS. 4a-4d, discloses an actuation member formed by 21axe2x80x2 and a bearing member/housing 35 and a valve member 36. The actuation member upon coupling urges the ball 19xe2x80x2 off its seat and permits upstream pressure to be vented into chamber 26xe2x80x2 as indicated by flow arrow 71.
U.S. patent application Ser. No. 09/193,346 filed Nov. 17, 1998 now U.S. Pat. No. 6,095,190 issued Aug. 1, 2000. That application disclosed a coupling with a female half having internal pressure relief. The pressure relief is accomplished in part by a ball valve which engages an interior seat of the main valve. A flat edged push pin is employed to operate the ball valve and the main valve includes at least one relief port which communicates with a passageway formed by a bore in the main valve and the push pin.
The related art also includes a design by Parker Hannifin Corporation. The design includes a main valve which floats leftwardly and rightwardly into and out of engagement with an adaptor. The seal formed between the main valve and the adaptor is a metal to metal seal. Further, a metal to metal seal is formed between the relief valve and the main valve. These metal to metal seals can and do leak which cause the application of high pressure in the adaptor to the relief valve and its threaded extension. The threaded extension of the Parker Hannifin design provides a large surface area upon which fluid under pressure may act which leaks by either the main valve or the relief valve. This causes the stripping of the relief valve as it is literally pushed and pulled through the main valve or the relief valve extension breaks loose of the relief valve or the relief valve and its extension fracture due to the large tensile forces created by the large pressure.
None of the related art, however, provides for a balanced male coupling half having a stable and reliable internal pressure relief valve. The instant invention provides a strong pressure relief valve and a large capacity reservoir for the relief of high pressure. Further, due to the balanced nature of the male half of the coupling in combination with a dry space or volume between the flush face sliding sleeve, the pressure relief valve, and the principal valve, pressure relief in the conduits connected upstream of the male half of the coupling is easily achieved.
A coupling half comprising: a body; a principal valve seating against the body/adaptor and unseating therefrom; a relief valve seating against the principal valve and unseating therefrom; and, a flush face sliding sleeve valve seating against the body and unseating therefrom is disclosed. When the flush face sliding sleeve valve unseats from the body it travels toward the relief valve and engages the relief valve unseating the relief valve from the principal valve permitting flow by the relief valve and enabling the principal valve to unseat from the body. The principal valve is closed until the male and the female halves of the coupling have been sufficiently connected.
The relief valve and the principal valve define an annulus therebetween. The area of the relief valve exposed to pressure is small so as to minimize the forces applied to the relief valve which tend to pull the relief valve through the principal valve. When disconnected, pressurized fluid from the adaptor may leak by a metal to metal seal formed between the relief valve and the principal valve. Further, pressurized fluid may leak by the seal between the principal valve and the adaptor. The relief valve is substantially cylindrical with its maximum diameter being 1.7 times its minimum diameter.
The principal valve includes a passageway for relieving pressure upstream of the principal valve. As the relief valve unseats from the principal valve, flow is permitted to the annulus defined by the relief valve and the principal valve and through the passageway in the principal valve and to a reservoir generally defined by the principal valve and the body. This causes a reduction in pressure upstream of the principal valve which enables the principal valve to unseat from the body. Usually an adaptor is affixed to the body such that the principal valve seats against the adaptor.
A first balanced seal resides in a circumferential groove in the body of the coupling half and prevents the escape of fluid from the coupling half and a second balanced seal resides in a first circumferential groove of the principal valve and prevents intrusion of fluid into a volume generally bounded by the interior of the flush face sliding sleeve valve, and the exteriors of the relief valve and principal valve. The principal valve and the relief valve both include extensions which are threaded thereto. The principal valve and relief valve as used herein refer to the principal valve and the relief valve together with their respective extensions.
An annulus, or reservoir, is formed between said principal valve and the body. A yoke and a first spring are disclosed and the first spring is operable between the body and the yoke urging the yoke into engagement with the flush face sliding sleeve valve. A seal resides in a second circumferential groove of the principal valve and prevents intrusion of fluid into a volume generally bounded by the interior of the flush face sliding sleeve valve, and the exteriors of the relief valve and principal valve.
A second spring is operable between a shoulder on the relief valve and the principal valve. Extensions of the principal and relief valves are threaded to the principal and the relief valve, respectively.
Accordingly, it is an object of the present invention to provide a male coupling half with internal pressure relief past the principal valve so as to provide easy connection under pressure with upstream pressure applied to the principal valve and the male coupling half.
It is a further object of the present invention to provide a male coupling half which has pressure balanced valving to enable easy connection with pressure on the male coupling half.
It is a further object of the present invention to provide a male coupling half having a volume generally bounded by the interior of the flush face sliding sleeve valve, and the exteriors of the relief valve and principal valve which does not have fluid therein. Put another way, it is an object to maintain the volume dry.
It is an object of the instant invention to provide a coupling half which may be used in one quarter inch couplings. These small couplings necessitate small relief valves which do not fracture employing the teachings of the instant invention.
These and other objects of the invention will be better understood when taken in conjunction with the Brief Description of the Drawings, the Description of the Invention, the Drawings and the Claims which follow hereinbelow.